Non-Oxidizing Biocide: Nonionic

Is microbial growth fouling your system? If left unchecked, microbial contamination can reduce heat transfer efficiency, cause corrosion and create potential health and safety issues.

AQUAGUARD 665 is a nonionic, fast acting, effective broad spectrum biocide that can be used at low levels to control slime forming bacteria, sulphate reducing bacteria (SRB) and algae.

AQUAGUARD 665 is also highly effective at removing existing biofilms and inhibiting regrowth; and at controlling legionella pneumophila also known as Legionnaire’s Disease Bacteria, a common microbial contaminant in cooling and humidification systems.


  • Effective, broad spectrum antimicrobial agent (biocide)
  • Economical, low dosages required to kill and inhibit a wide variety of microbial contaminants
  • Nonionic. Compatible with typical water treatment programs including scale and corrosion inhibitors and dispersants.
  • Non-oxidizing and formaldehyde free
  • Non-foaming
  • Effective over a broad pH range
  • Persistent in the system over a period of time resulting in reduced biocide usage
  • Readily biodegradable when diluted to less than minimum inhibitory concentration (MIC)


AQUAGUARD 665 is registered for use with the Pest Management Regulatory Agency for the control of microorganisms in recirculating cooling and service water, and auxiliary systems, as well as heat transfer and industrial wastewater systems. Other uses include air washers, paper mills, and oilfield, as well as preservation of aqueous metalworking fluids and some in-can product preservation applications.

Click here to view the full product label.

Here’s What a Guardian Chemicals
Partnership Looks Like
Step 1
Get in Touch speech bubble icon
Get in touch

Our experts know your industry and will seek to understand the unique challenges of your business. Let’s talk.

Step 2
Truck icon
We come to you

Your systems and processes are interconnected. We’ll arrange a site visit to understand the bigger picture.

Step 3
Lab test tube icon
We propose a solution
A solution is more than just a product—it is a complete program that results in lower life cycle operating cost and considers the impact on health, safety and the environment.
Step 4
Delivery box icon
We deliver fast
Our service is key to your success. We deliver with industry-leading turnaround times, and effective commissioning and training ensure that your system operates safely and effectively from day one.
Ready to Experience the Difference Guardian Chemicals Can Make?

Talk to our team for advice, quotes, and purchasing.

Contact us headphone icon
Contact an industry expert: